Cutting Saturated Fat Intake Won’t Prevent Heart Disease: Study

New research led by the University of Cambridge may give butter lovers everywhere a reason to rejoice. Published in the March 18 edition of Annals of Internal Medicine, the study raises questions about the current guidelines that call for restrictions on the consumption of saturated fats to prevent heart disease.

The international research collaboration analyzed existing cohort studies and randomized trials on links between coronary heart risk and fatty acid intake. Based on their findings, reducing saturated fats in a diet does not prevent heart disease. The team also found insufficient reasoning for guidelines that advocate higher consumption of polyunsaturated fats to reduce coronary disease risk.

Also, the team found that specific fatty acid subtypes – such as different types of omega 3 – varied widely on cardiovascular risk, which raises questions about existing dietary guidelines that focus mainly on the total amount of fat from saturated or unsaturated sources rather than food sources of the fatty acid subtypes.

“These are interesting results that potentially stimulate new lines of scientific inquiry and encourage careful reappraisal of our current nutritional guidelines,” Dr Rajiv Chowdhury, lead author of the study from the University of Cambridge, said in a statement.

“Cardiovascular disease, in which the principal manifestation is coronary heart disease, remains the single leading cause of death and disability worldwide,” he said. “In 2008, more than 17 million people died from a cardiovascular cause globally. With so many affected by this illness, it is critical to have appropriate prevention guidelines which are informed by the best available scientific evidence.”

However, heart experts stress that the findings do not mean people have clear access to load up on cheese, pies and other fatty foods. Too much saturated fat can increase the amount of cholesterol in the blood, which in turn can lead to an increased risk of developing coronary heart disease, according to a report from the BBC.

Saturated fat is found in a host of foods, including sausage, bacon, butter, cheese and cream. And most people eat too much of these foods. Current guidelines recommend men limit saturated fat intake to 30g a day and women 20g a day, reports the BBC.

But the new study says that the drive to get more people to eat unsaturated fats such as olive and sunflower oils rather than animal fats, is lacking some credibility.

For their meta-analysis, the team analyzed data from 72 studies including more than 600,000 participants across 18 countries. The research team found that total saturated fatty acid, whether measured in the diet or in the bloodstream, was not associated with coronary disease risk in observational studies. In assessment studies, the team found similarly non-significant associations between consumption of fatty acids and cardiovascular risk.

Interestingly, the team found some evidence that circulating levels of eicosapentaenoic and docosahexaenoic acids (two main types of long-chain omega-3 polyunsaturated fatty acids) and arachidonic acid (omega-6) are each associated with lower coronary risk. The team also found weak positive links between circulating palmitic and stearic acids (found in palm oils and animals fats, respectively) and cardiovascular disease. Furthermore, they found that circulating margaric acid (a dairy fat) significantly reduced the risk of heart disease.

When it came to omega-3 and omega-6 fatty acid supplements used to reduce the risk of coronary heart disease, the team found no significant effects in analysis of randomized controlled trials, indicating a lack of benefit from these nutrients.

Still, trans fats are strongly and positively associated with risk of heart disease. These artificial fats, which are found in processed foods and margarine spreads, should be regulated and avoided, according to the study authors.

Despite all the latest good news for butter lovers, the British Heart Foundation (BHF) said the findings do not change the current advice that eating too much fat is harmful to the heart.

“This analysis of existing data suggests there isn’t enough evidence to say that a diet rich in polyunsaturated fats but low in saturated fats reduces the risk of cardiovascular disease. But large scale clinical studies are needed, as these researchers recommend, before making a conclusive judgement,” said Prof Jeremy Pearson, Associate Medical Director of the BHF, which helped fund the study.

“Alongside taking any necessary medication, the best way to stay heart healthy is to stop smoking, stay active, and ensure our whole diet is healthy – and this means considering not only the fats in our diet but also our intake of salt, sugar and fruit and vegetables,” he added.